Field
Aspects of the present invention generally relate to a cartridge provided with an electrophotographic photosensitive drum for use in an electrophotographic image forming apparatus and also relates to a cover member.
Description of the Related Art
In an electrophotographic image forming apparatus (hereinafter, simply referred to as an image forming apparatus as well), a photosensitive member typically having a drum shape, or in other words, a photosensitive drum that serves as an image carrying member, is charged uniformly. Then, the charged photosensitive drum is selectively exposed, and an electrostatic latent image (electrostatic image) is formed on the photosensitive drum. The electrostatic latent image formed on the photosensitive drum is then developed into a toner image using toner serving as a developer. Thereafter, the toner image formed on the photosensitive drum is transferred onto a recording material, such as a recording sheet or a plastic sheet, and the toner image transferred to the recording material is heated and pressurized, whereby the toner image is fixed on the recording material and an image is thus recorded.
Such an image forming apparatus typically needs to be replenished with toner and requires maintenance on various process units therein. In order to facilitate the toner replenishment or the maintenance, a process cartridge is put into practice in which a photosensitive drum, a charging unit, a developing unit, a cleaning unit, and so on are located collectively within a frame and integrated into a cartridge that can be mounted on and detached from an image forming apparatus main body.
This process cartridge system enables a user to carry out maintenance on the image forming apparatus by themselves, which significantly improves the operability of the image forming apparatus, making it possible to provide an image forming apparatus that shows good usability. Therefore, the process cartridge system is widely used in image forming apparatuses.
According to Japanese Patent Application Laid-Open No. 10-20660, the process cartridge described above is provided with a cover member that is fixed at one end in the axial direction of the photosensitive drum (hereinafter, the longitudinal direction) to a frame and rotationally supports the photosensitive drum. The cover member is provided with a planar portion extending along a plane orthogonal to the axial direction of the photosensitive drum and a first convex portion extending from the planar portion toward the outside in the longitudinal direction. The first convex portion is positioned and supported by a positioning portion provided in the image forming apparatus (hereinafter, simply referred to as an apparatus main body as well), and thus the process cartridge performs positioning relative to the apparatus main body.